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CUET · MATHS · PYQ PAPER 2023

For the matrix \(A=\left[\begin{array}{ll}3 & 1 \\ 7 & 5\end{array}\right], 8 A^{-1}=\) ‾‾‾‾‾‾‾‾‾‾

  1. A I - A
  2. B \(\frac{1}{8}(A- I )\)
  3. C \((8 I - A )\)
  4. D \(\frac{1}{8}( I + A )\)
Verified Solution

Answer & Solution

Correct Answer

(C) \((8 I - A )\)

Step-by-step Solution

Detailed explanation

\(det(A) = (3)(5) - (1)(7) = 15 - 7 = 8\) \(A^{-1} = \frac{1}{det(A)} \text{adj}(A) = \frac{1}{8}\left[\begin{array}{cc} 5 & -1 \\ -7 & 3\end{array}\right]\)…